Disease relevance of RNASEN

• RESULTS: We found that RNASEN expression levels were enhanced in a fraction of esophageal cancers [1].
• We studied the expression level of the miRNA processing enzyme (DICER1, DGCR8, and RNASEN) in esophageal squamous cell carcinoma (ESCC) [1].
• The Microprocessor complex comprises Drosha and the double-stranded RNAbinding protein DiGeorge syndrome critical region 8 gene (DGCR8), which is deleted in DiGeorge syndrome (15, 16) [2].
• We have generated mutations in human Dicer and Escherichia coli RNase III residues implicated in the catalysis, and studied their effect on RNA processing [3].
• RNase III cuts some single-stranded RNAs, such as bacteriophage T7 early RNA, at specific sites in vivo [4].

High impact information on RNASEN

• Molecular basis for the recognition of primary microRNAs by the Drosha-DGCR8 complex [5].
• While Dicer, which produces small interfering RNAs, is currently the focus of intense interest, the structurally simpler bacterial RNase III serves as a paradigm for the entire family [6].
• A pattern of protein-RNA interactions, defined by four RNA binding motifs in RNase III and three protein-interacting boxes in dsRNA, is responsible for substrate specificity, while conserved amino acid residues and divalent cations are responsible for scissile-bond cleavage [6].
• The structure reveals a wealth of information about the mechanism of RNA hydrolysis that can be extrapolated to other RNase III family members [6].
• Based on these and other data, we propose that Dicer functions through intramolecular dimerization of its two RNase III domains, assisted by the flanking RNA binding domains, PAZ and dsRBD [3].

Biological context of RNASEN

• The role of RNASEN in cell proliferation in ESCC cells was assessed by small interfering RNA [1].
• Knockdown of RNASEN in esophageal cancer cell lines resulted in a 46% to 85% reduction in cell number [1].
• EXPERIMENTAL DESIGN: The expression levels of DICER1, DGCR8, and RNASEN mRNA in 73 ESCC tissues were compared with that in corresponding normal esophageal epithelium by Taqman real-time reverse-transcription PCR [1].
• RNase III proteins play key roles in microRNA (miRNA) biogenesis [7].
• How Drosha recognizes primary RNA substrates and selects its cleavage sites has remained a mystery, especially given that the known targets for Drosha processing show no discernable sequence homology [8].

Anatomical context of RNASEN

• We also examined RNASEN protein expression in 27 cell lines [1].
• In an immunohistochemical study, the intensity of RNASEN expression was often increased in the tumor compared with that in normal epithelium [1].
• BACKGROUND: Members of the ribonuclease III superfamily of double-stranded(ds)-RNA-specific endoribonucleases participate in diverse RNA maturation and decay pathways in eukaryotic and prokaryotic cells [9].
• It is suggested that conversion between these structures may have a role in termination; this may be influenced by interactions with ribosomes and RNase III [10].
• Identification of putative rat ribonuclease III by differential display: a novel rat mRNA expressed in a circadian manner in the rat suprachiasmatic nucleus [11].

Associations of RNASEN with chemical compounds

• The bridging phosphinidene complexes [Mn2(CO)8(micro-PNiPr2)] and [Co2(CO)4(micro-dppm)(micro-PNR2)](NR2=NiPr2, TMP) react with heterocumulenes RN3, CH2N2 and Ph2C=N=N to form complexes with micro-eta1,eta2-aminophosphaimine, micro-eta1,eta2-aminophosphaalkene and micro-eta1,eta2-aminophosphadiphenylmethylazaimine ligands, respectively [12].
• Intron-encoded and polycistronic snoRNAs are released from primary transcripts as pre-snoRNAs by the spliceosome or by an RNase III-like activity, respectively [13].
• On the basis of structural, genetic, and biological data, we have constructed a hypothetical model of Aa-RNase III in complex with dsRNA and Mg(2+) ion, which provides the first glimpse of RNase III in action [14].
• They were digested by RNase III in a buffer containing manganese ions, then separated on 15% non-denaturing PAGE, and the siRNAs about 25 bp in length were recovered. siRNAs prepared with CFDP were co-transfected with target gene expression plasmid into human cell lines with lipofectamine 2,000 to test their inhibition efficiency [15].
• To assess the involvement of the RNA cleavage site-proximal 2' hydroxyl group in the RNase III catalytic mechanism, a specific processing substrate was chemically synthesized to contain a 2'-deoxyribose residue at the scissile phosphodiester bond [16].

Physical interactions of RNASEN

• In this complex, Drosha interacts with DGCR8, which contains two double-stranded RNA (dsRNA)-binding domains [7].

Enzymatic interactions of RNASEN

• The bidentate RNase III Dicer cleaves microRNA precursors to generate the 21-23 nt long mature RNAs [17].

Other interactions of RNASEN

• Two members of the ribonuclease (RNase) III endonuclease protein family, Drosha and Dicer, have been implicated in this two-step processing (10-13) [2].
• The Drosha-DGCR8 complex initiates microRNA maturation by precise cleavage of the stem loops that are embedded in primary transcripts (pri-miRNAs) [5].
• The discrepancy between pri-miRNA and miR expression following overload was not explained by a change in the expression of components of the miRNA biogenesis pathway, since Drosha and Exportin-5 transcript levels were significantly increased by 50% in response to functional overload, whereas Dicer expression remained unchanged [18].
• In vitro RNA-RNA binding experiments demonstrated that the incubation of expanded CUG repeats with CUGBP1 RNA generated a higher molecular weight band, which was digested by RNase III [19].
• Drosha versus ADAR: wrangling over pri-miRNA [20].

Analytical, diagnostic and therapeutic context of RNASEN

• Fluorescent in situ hybridization demonstrates that the mouse RNase III gene maps to chromosome 15, region B, and that the human RNase III gene maps to a syntenic location on chromosome 5p13-p14 [9].
• Ribonuclease III from Escherichia coli has been purified to apparent homogeneity by affinity chromatography on immobilized double-stranded RNA [4].
• Sequence analysis of the 330-kb genome of chlorella virus PBCV-1 revealed an open reading frame, A464R, which encodes a protein with 30-35% amino acid identity to ribonuclease III (RNase III) from many bacteria [21].
• Here we report the use of differential display reverse transcriptase polymerase chain reaction to identify a novel rat mRNA sequence which is highly homologous to human ribonuclease III [11].
• Crystallization and preliminary X-ray analysis of the C-terminal RNase III domain of human Dicer [22].

References